Steam-superheater.



J. PRIMROSE. STE AM SUPERHEATER.

APPLICATION FILED AUG15,1914.

1,171,353. Patented Feb. 8,1916.

(gs wanton $1 elm M I JOHN PRIMROSE, F DONGAN HILLS, NEW YORK.

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I To all whom it may) concern: I i

Superheaters, of which the followingis a full, clear, and exact description.

Superheaters for steam boilers, in the.

form oftubes, coils or boxes, are usually combined with the boiler and furnace so as higher than that of t to receive heat directly from the same gases that generate the'steam in the boiler. It is, however, common practice to'separately fire section of a complete plant embodying the .invent on. v

the superheater by providingfor its coils a special and independently fixed furnace, and to this latter classof apparatus the invention, subject ofmy present applicatiomre-g lates.

The tempera'turelevels through a superheater are considerably higher than those of a steam boiler, the averagetemperatu're of' the steam in the former belng, under con-.

ditions that may beaccepted asa basis forfair comparison, approximately 100 ,F.

t e water in a boiler. The temperature of the waste gases on leaving .the superheater would, therefore, be

correspondingly higher than that of the gases leaving the boiler, besides which itis .not possible to reduce thetemperature by extending the heating surface or by lowering the temperature of its contents at any point, as in the case of a boiler. The efficiency, however, of all such devices depending directly upon the extent to which heat is extracted from'the gases, it'follows that the apparatus is the most economical and efiicient which delivers to the atmosphere waste gases of lowest temperature. In this respectsuperheaters have of necessity been always at a disadvantage-in; comparison with boilers. v

The primary object of my invention is to increase the efficiency of superheaters and to bring them more nearly on a par in this regard, with the forms of apparatus involving heating-furnaces, and to this 'end'the improvement consists in. the combination with .a separately fired super-heater of a means for extracting the heat from the gases after leaving the Superh'eater, and

transferring it directly to the air which supports combustion. As a result of such 1mprovementthere is secured the efl'ect of a regenerator by which heat is transferred Specification of Letters Patent.

Patented Feb. 8, 1916.

u Application filed August 15, 1914. Serial in. $56,903.

leaving the superheater may be reduced to any desired point, limited only by that of the atmosphere. The means for carrying out this invention,

obviously, may vary, within wide limits,

but. in the accompanying drawing I have illustrated a .form which is typical of the most approved arrangement known to me for the purpose.

The drawing is a view in longitudinal A is a furnace, the heating chamber of which contains a superheater B ofany'suitable form, over the tubes of which pass the hot gases from the fire on the grate bars C.

The heating chamber is extended-beyond the superheater and is designed with reference thereto to provide a space intermediate the superheater and the/chimney D, within which is located a series of tubes E, or any equivalents therefor, forming part of a duct or passage F F carried through said chamber for conveying fresh air to the space below the grate bars. started the draft doors G G are closed and the air for supporting combustion is drawn through the duct F F and tubes E by the chimney pull or if that is not suflicient forced through saidduct by any suitable means, not shown in the drawings. In this way a large proportion of the heat of the gases after leaving the superheater is ab: sorbed by the air passing through the tubes E and utilized for the further heating of the superheater.

After the fire is I am aware that regeneration effected by raising the temperature of the air supply by heat absorbed from the waste furnace or flue gases is not'new, having been applied in connection with steam boilers, blast fur- 12, 1893. The primary object of the three.

rows of tubes T, shown in the Uhler patent is to preserve the lower rows of superheater tubes from excessive heating. He spec fically states, among other things, that ina group ofi-superheater tubes the three lower rows, that is those closest tothe furnace, alone can'become red hot by excessive heating, and in order to protect the superheater tubes he interposes the tubes -T through which cold air is adapted to enter ,the furnace above the fire through nozzles U U for the purpose of consuming smoke. I find, however, that economical'considerations require that the superheater be subjected to the gases immediately issuing from the furnace and thereafter extracting the remaining. heat energy from said gases. way, and in this way only, can the maximum amount oithe heat from said furnace gases be utilized.

In this rectly to the air which supports combustion.

JOHN PniMnosn.

. Witnesses: Y

THOMAS J. BYRNE, Wmnmm: 1P. JonrNsoN. 

